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main.c 18.57 KiB
/*
* drivers/base/power/main.c - Where the driver meets power management.
*
* Copyright (c) 2003 Patrick Mochel
* Copyright (c) 2003 Open Source Development Lab
*
* This file is released under the GPLv2
*
*
* The driver model core calls device_pm_add() when a device is registered.
* This will intialize the embedded device_pm_info object in the device
* and add it to the list of power-controlled devices. sysfs entries for
* controlling device power management will also be added.
*
* A separate list is used for keeping track of power info, because the power
* domain dependencies may differ from the ancestral dependencies that the
* subsystem list maintains.
*/
#include <linux/device.h>
#include <linux/kallsyms.h>
#include <linux/mutex.h>
#include <linux/pm.h>
#include <linux/resume-trace.h>
#include <linux/rwsem.h>
#include "../base.h"
#include "power.h"
/*
* The entries in the dpm_list list are in a depth first order, simply
* because children are guaranteed to be discovered after parents, and
* are inserted at the back of the list on discovery.
*
* Since device_pm_add() may be called with a device semaphore held,
* we must never try to acquire a device semaphore while holding
* dpm_list_mutex.
*/
LIST_HEAD(dpm_list);
static DEFINE_MUTEX(dpm_list_mtx);
/*
* Set once the preparation of devices for a PM transition has started, reset
* before starting to resume devices. Protected by dpm_list_mtx.
*/
static bool transition_started;
/**
* device_pm_lock - lock the list of active devices used by the PM core
*/
void device_pm_lock(void)
{
mutex_lock(&dpm_list_mtx);
}
/**
* device_pm_unlock - unlock the list of active devices used by the PM core
*/
void device_pm_unlock(void)
{
mutex_unlock(&dpm_list_mtx);
}
/**
* device_pm_add - add a device to the list of active devices
* @dev: Device to be added to the list
*/
void device_pm_add(struct device *dev){
pr_debug("PM: Adding info for %s:%s\n",
dev->bus ? dev->bus->name : "No Bus",
kobject_name(&dev->kobj));
mutex_lock(&dpm_list_mtx);
if (dev->parent) {
if (dev->parent->power.status >= DPM_SUSPENDING)
dev_warn(dev, "parent %s should not be sleeping\n",
dev->parent->bus_id);
} else if (transition_started) {
/*
* We refuse to register parentless devices while a PM
* transition is in progress in order to avoid leaving them
* unhandled down the road
*/
WARN_ON(true);
}
list_add_tail(&dev->power.entry, &dpm_list);
mutex_unlock(&dpm_list_mtx);
}
/**
* device_pm_remove - remove a device from the list of active devices
* @dev: Device to be removed from the list
*
* This function also removes the device's PM-related sysfs attributes.
*/
void device_pm_remove(struct device *dev)
{
pr_debug("PM: Removing info for %s:%s\n",
dev->bus ? dev->bus->name : "No Bus",
kobject_name(&dev->kobj));
mutex_lock(&dpm_list_mtx);
list_del_init(&dev->power.entry);
mutex_unlock(&dpm_list_mtx);
}
/**
* pm_op - execute the PM operation appropiate for given PM event
* @dev: Device.
* @ops: PM operations to choose from.
* @state: PM transition of the system being carried out.
*/
static int pm_op(struct device *dev, struct pm_ops *ops, pm_message_t state)
{
int error = 0;
switch (state.event) {
#ifdef CONFIG_SUSPEND
case PM_EVENT_SUSPEND:
if (ops->suspend) {
error = ops->suspend(dev);
suspend_report_result(ops->suspend, error);
}
break;
case PM_EVENT_RESUME:
if (ops->resume) {
error = ops->resume(dev);
suspend_report_result(ops->resume, error);
}
break;
#endif /* CONFIG_SUSPEND */
#ifdef CONFIG_HIBERNATION
case PM_EVENT_FREEZE:
case PM_EVENT_QUIESCE:
if (ops->freeze) {
error = ops->freeze(dev);
suspend_report_result(ops->freeze, error);
} break;
case PM_EVENT_HIBERNATE:
if (ops->poweroff) {
error = ops->poweroff(dev);
suspend_report_result(ops->poweroff, error);
}
break;
case PM_EVENT_THAW:
case PM_EVENT_RECOVER:
if (ops->thaw) {
error = ops->thaw(dev);
suspend_report_result(ops->thaw, error);
}
break;
case PM_EVENT_RESTORE:
if (ops->restore) {
error = ops->restore(dev);
suspend_report_result(ops->restore, error);
}
break;
#endif /* CONFIG_HIBERNATION */
default:
error = -EINVAL;
}
return error;
}
/**
* pm_noirq_op - execute the PM operation appropiate for given PM event
* @dev: Device.
* @ops: PM operations to choose from.
* @state: PM transition of the system being carried out.
*
* The operation is executed with interrupts disabled by the only remaining
* functional CPU in the system.
*/
static int pm_noirq_op(struct device *dev, struct pm_ext_ops *ops,
pm_message_t state)
{
int error = 0;
switch (state.event) {
#ifdef CONFIG_SUSPEND
case PM_EVENT_SUSPEND:
if (ops->suspend_noirq) {
error = ops->suspend_noirq(dev);
suspend_report_result(ops->suspend_noirq, error);
}
break;
case PM_EVENT_RESUME:
if (ops->resume_noirq) {
error = ops->resume_noirq(dev);
suspend_report_result(ops->resume_noirq, error);
}
break;
#endif /* CONFIG_SUSPEND */
#ifdef CONFIG_HIBERNATION
case PM_EVENT_FREEZE:
case PM_EVENT_QUIESCE:
if (ops->freeze_noirq) {
error = ops->freeze_noirq(dev);
suspend_report_result(ops->freeze_noirq, error);
}
break;
case PM_EVENT_HIBERNATE:
if (ops->poweroff_noirq) {
error = ops->poweroff_noirq(dev);
suspend_report_result(ops->poweroff_noirq, error);
}
break; case PM_EVENT_THAW:
case PM_EVENT_RECOVER:
if (ops->thaw_noirq) {
error = ops->thaw_noirq(dev);
suspend_report_result(ops->thaw_noirq, error);
}
break;
case PM_EVENT_RESTORE:
if (ops->restore_noirq) {
error = ops->restore_noirq(dev);
suspend_report_result(ops->restore_noirq, error);
}
break;
#endif /* CONFIG_HIBERNATION */
default:
error = -EINVAL;
}
return error;
}
static char *pm_verb(int event)
{
switch (event) {
case PM_EVENT_SUSPEND:
return "suspend";
case PM_EVENT_RESUME:
return "resume";
case PM_EVENT_FREEZE:
return "freeze";
case PM_EVENT_QUIESCE:
return "quiesce";
case PM_EVENT_HIBERNATE:
return "hibernate";
case PM_EVENT_THAW:
return "thaw";
case PM_EVENT_RESTORE:
return "restore";
case PM_EVENT_RECOVER:
return "recover";
default:
return "(unknown PM event)";
}
}
static void pm_dev_dbg(struct device *dev, pm_message_t state, char *info)
{
dev_dbg(dev, "%s%s%s\n", info, pm_verb(state.event),
((state.event & PM_EVENT_SLEEP) && device_may_wakeup(dev)) ?
", may wakeup" : "");
}
static void pm_dev_err(struct device *dev, pm_message_t state, char *info,
int error)
{
printk(KERN_ERR "PM: Device %s failed to %s%s: error %d\n",
kobject_name(&dev->kobj), pm_verb(state.event), info, error);
}
/*------------------------- Resume routines -------------------------*/
/**
* resume_device_noirq - Power on one device (early resume).
* @dev: Device.
* @state: PM transition of the system being carried out.
*
* Must be called with interrupts disabled.
*/
static int resume_device_noirq(struct device *dev, pm_message_t state)
{
int error = 0;
TRACE_DEVICE(dev);
TRACE_RESUME(0);
if (!dev->bus)
goto End;
if (dev->bus->pm) {
pm_dev_dbg(dev, state, "EARLY ");
error = pm_noirq_op(dev, dev->bus->pm, state);
} else if (dev->bus->resume_early) {
pm_dev_dbg(dev, state, "legacy EARLY ");
error = dev->bus->resume_early(dev);
}
End:
TRACE_RESUME(error);
return error;
}
/**
* dpm_power_up - Power on all regular (non-sysdev) devices.
* @state: PM transition of the system being carried out.
*
* Execute the appropriate "noirq resume" callback for all devices marked
* as DPM_OFF_IRQ.
*
* Must be called with interrupts disabled and only one CPU running.
*/
static void dpm_power_up(pm_message_t state)
{
struct device *dev;
list_for_each_entry(dev, &dpm_list, power.entry)
if (dev->power.status > DPM_OFF) {
int error;
dev->power.status = DPM_OFF;
error = resume_device_noirq(dev, state);
if (error)
pm_dev_err(dev, state, " early", error);
}
}
/**
* device_power_up - Turn on all devices that need special attention.
* @state: PM transition of the system being carried out.
*
* Power on system devices, then devices that required we shut them down
* with interrupts disabled.
*
* Must be called with interrupts disabled.
*/
void device_power_up(pm_message_t state)
{
sysdev_resume();
dpm_power_up(state);
}
EXPORT_SYMBOL_GPL(device_power_up);
/**
* resume_device - Restore state for one device.
* @dev: Device.
* @state: PM transition of the system being carried out.
*/
static int resume_device(struct device *dev, pm_message_t state)
{
int error = 0;
TRACE_DEVICE(dev);
TRACE_RESUME(0);
down(&dev->sem);
if (dev->bus) {
if (dev->bus->pm) {
pm_dev_dbg(dev, state, "");
error = pm_op(dev, &dev->bus->pm->base, state);
} else if (dev->bus->resume) {
pm_dev_dbg(dev, state, "legacy ");
error = dev->bus->resume(dev);
}
if (error)
goto End;
}
if (dev->type) {
if (dev->type->pm) {
pm_dev_dbg(dev, state, "type ");
error = pm_op(dev, dev->type->pm, state);
} else if (dev->type->resume) {
pm_dev_dbg(dev, state, "legacy type ");
error = dev->type->resume(dev);
}
if (error)
goto End;
}
if (dev->class) {
if (dev->class->pm) {
pm_dev_dbg(dev, state, "class ");
error = pm_op(dev, dev->class->pm, state);
} else if (dev->class->resume) {
pm_dev_dbg(dev, state, "legacy class ");
error = dev->class->resume(dev);
}
}
End:
up(&dev->sem);
TRACE_RESUME(error);
return error;
}
/**
* dpm_resume - Resume every device.
* @state: PM transition of the system being carried out.
*
* Execute the appropriate "resume" callback for all devices the status of
* which indicates that they are inactive.
*/
static void dpm_resume(pm_message_t state)
{
struct list_head list;
INIT_LIST_HEAD(&list);
mutex_lock(&dpm_list_mtx);
transition_started = false;
while (!list_empty(&dpm_list)) {
struct device *dev = to_device(dpm_list.next);
get_device(dev);
if (dev->power.status >= DPM_OFF) {
int error;
dev->power.status = DPM_RESUMING;
mutex_unlock(&dpm_list_mtx);
error = resume_device(dev, state);
mutex_lock(&dpm_list_mtx); if (error)
pm_dev_err(dev, state, "", error);
} else if (dev->power.status == DPM_SUSPENDING) {
/* Allow new children of the device to be registered */
dev->power.status = DPM_RESUMING;
}
if (!list_empty(&dev->power.entry))
list_move_tail(&dev->power.entry, &list);
put_device(dev);
}
list_splice(&list, &dpm_list);
mutex_unlock(&dpm_list_mtx);
}
/**
* complete_device - Complete a PM transition for given device
* @dev: Device.
* @state: PM transition of the system being carried out.
*/
static void complete_device(struct device *dev, pm_message_t state)
{
down(&dev->sem);
if (dev->class && dev->class->pm && dev->class->pm->complete) {
pm_dev_dbg(dev, state, "completing class ");
dev->class->pm->complete(dev);
}
if (dev->type && dev->type->pm && dev->type->pm->complete) {
pm_dev_dbg(dev, state, "completing type ");
dev->type->pm->complete(dev);
}
if (dev->bus && dev->bus->pm && dev->bus->pm->base.complete) {
pm_dev_dbg(dev, state, "completing ");
dev->bus->pm->base.complete(dev);
}
up(&dev->sem);
}
/**
* dpm_complete - Complete a PM transition for all devices.
* @state: PM transition of the system being carried out.
*
* Execute the ->complete() callbacks for all devices that are not marked
* as DPM_ON.
*/
static void dpm_complete(pm_message_t state)
{
struct list_head list;
INIT_LIST_HEAD(&list);
mutex_lock(&dpm_list_mtx);
while (!list_empty(&dpm_list)) {
struct device *dev = to_device(dpm_list.prev);
get_device(dev);
if (dev->power.status > DPM_ON) {
dev->power.status = DPM_ON;
mutex_unlock(&dpm_list_mtx);
complete_device(dev, state);
mutex_lock(&dpm_list_mtx);
}
if (!list_empty(&dev->power.entry))
list_move(&dev->power.entry, &list);
put_device(dev);
} list_splice(&list, &dpm_list);
mutex_unlock(&dpm_list_mtx);
}
/**
* device_resume - Restore state of each device in system.
* @state: PM transition of the system being carried out.
*
* Resume all the devices, unlock them all, and allow new
* devices to be registered once again.
*/
void device_resume(pm_message_t state)
{
might_sleep();
dpm_resume(state);
dpm_complete(state);
}
EXPORT_SYMBOL_GPL(device_resume);
/*------------------------- Suspend routines -------------------------*/
/**
* resume_event - return a PM message representing the resume event
* corresponding to given sleep state.
* @sleep_state: PM message representing a sleep state.
*/
static pm_message_t resume_event(pm_message_t sleep_state)
{
switch (sleep_state.event) {
case PM_EVENT_SUSPEND:
return PMSG_RESUME;
case PM_EVENT_FREEZE:
case PM_EVENT_QUIESCE:
return PMSG_RECOVER;
case PM_EVENT_HIBERNATE:
return PMSG_RESTORE;
}
return PMSG_ON;
}
/**
* suspend_device_noirq - Shut down one device (late suspend).
* @dev: Device.
* @state: PM transition of the system being carried out.
*
* This is called with interrupts off and only a single CPU running.
*/
static int suspend_device_noirq(struct device *dev, pm_message_t state)
{
int error = 0;
if (!dev->bus)
return 0;
if (dev->bus->pm) {
pm_dev_dbg(dev, state, "LATE ");
error = pm_noirq_op(dev, dev->bus->pm, state);
} else if (dev->bus->suspend_late) {
pm_dev_dbg(dev, state, "legacy LATE ");
error = dev->bus->suspend_late(dev, state);
suspend_report_result(dev->bus->suspend_late, error);
}
return error;
}
/**
* device_power_down - Shut down special devices.
* @state: PM transition of the system being carried out.
* * Power down devices that require interrupts to be disabled.
* Then power down system devices.
*
* Must be called with interrupts disabled and only one CPU running.
*/
int device_power_down(pm_message_t state)
{
struct device *dev;
int error = 0;
list_for_each_entry_reverse(dev, &dpm_list, power.entry) {
error = suspend_device_noirq(dev, state);
if (error) {
pm_dev_err(dev, state, " late", error);
break;
}
dev->power.status = DPM_OFF_IRQ;
}
if (!error)
error = sysdev_suspend(state);
if (error)
dpm_power_up(resume_event(state));
return error;
}
EXPORT_SYMBOL_GPL(device_power_down);
/**
* suspend_device - Save state of one device.
* @dev: Device.
* @state: PM transition of the system being carried out.
*/
static int suspend_device(struct device *dev, pm_message_t state)
{
int error = 0;
down(&dev->sem);
if (dev->class) {
if (dev->class->pm) {
pm_dev_dbg(dev, state, "class ");
error = pm_op(dev, dev->class->pm, state);
} else if (dev->class->suspend) {
pm_dev_dbg(dev, state, "legacy class ");
error = dev->class->suspend(dev, state);
suspend_report_result(dev->class->suspend, error);
}
if (error)
goto End;
}
if (dev->type) {
if (dev->type->pm) {
pm_dev_dbg(dev, state, "type ");
error = pm_op(dev, dev->type->pm, state);
} else if (dev->type->suspend) {
pm_dev_dbg(dev, state, "legacy type ");
error = dev->type->suspend(dev, state);
suspend_report_result(dev->type->suspend, error);
}
if (error)
goto End;
}
if (dev->bus) {
if (dev->bus->pm) {
pm_dev_dbg(dev, state, "");
error = pm_op(dev, &dev->bus->pm->base, state);
} else if (dev->bus->suspend) {
pm_dev_dbg(dev, state, "legacy ");
error = dev->bus->suspend(dev, state); suspend_report_result(dev->bus->suspend, error);
}
}
End:
up(&dev->sem);
return error;
}
/**
* dpm_suspend - Suspend every device.
* @state: PM transition of the system being carried out.
*
* Execute the appropriate "suspend" callbacks for all devices.
*/
static int dpm_suspend(pm_message_t state)
{
struct list_head list;
int error = 0;
INIT_LIST_HEAD(&list);
mutex_lock(&dpm_list_mtx);
while (!list_empty(&dpm_list)) {
struct device *dev = to_device(dpm_list.prev);
get_device(dev);
mutex_unlock(&dpm_list_mtx);
error = suspend_device(dev, state);
mutex_lock(&dpm_list_mtx);
if (error) {
pm_dev_err(dev, state, "", error);
put_device(dev);
break;
}
dev->power.status = DPM_OFF;
if (!list_empty(&dev->power.entry))
list_move(&dev->power.entry, &list);
put_device(dev);
}
list_splice(&list, dpm_list.prev);
mutex_unlock(&dpm_list_mtx);
return error;
}
/**
* prepare_device - Execute the ->prepare() callback(s) for given device.
* @dev: Device.
* @state: PM transition of the system being carried out.
*/
static int prepare_device(struct device *dev, pm_message_t state)
{
int error = 0;
down(&dev->sem);
if (dev->bus && dev->bus->pm && dev->bus->pm->base.prepare) {
pm_dev_dbg(dev, state, "preparing ");
error = dev->bus->pm->base.prepare(dev);
suspend_report_result(dev->bus->pm->base.prepare, error);
if (error)
goto End;
}
if (dev->type && dev->type->pm && dev->type->pm->prepare) {
pm_dev_dbg(dev, state, "preparing type ");
error = dev->type->pm->prepare(dev);
suspend_report_result(dev->type->pm->prepare, error);
if (error) goto End;
}
if (dev->class && dev->class->pm && dev->class->pm->prepare) {
pm_dev_dbg(dev, state, "preparing class ");
error = dev->class->pm->prepare(dev);
suspend_report_result(dev->class->pm->prepare, error);
}
End:
up(&dev->sem);
return error;
}
/**
* dpm_prepare - Prepare all devices for a PM transition.
* @state: PM transition of the system being carried out.
*
* Execute the ->prepare() callback for all devices.
*/
static int dpm_prepare(pm_message_t state)
{
struct list_head list;
int error = 0;
INIT_LIST_HEAD(&list);
mutex_lock(&dpm_list_mtx);
transition_started = true;
while (!list_empty(&dpm_list)) {
struct device *dev = to_device(dpm_list.next);
get_device(dev);
dev->power.status = DPM_PREPARING;
mutex_unlock(&dpm_list_mtx);
error = prepare_device(dev, state);
mutex_lock(&dpm_list_mtx);
if (error) {
dev->power.status = DPM_ON;
if (error == -EAGAIN) {
put_device(dev);
continue;
}
printk(KERN_ERR "PM: Failed to prepare device %s "
"for power transition: error %d\n",
kobject_name(&dev->kobj), error);
put_device(dev);
break;
}
dev->power.status = DPM_SUSPENDING;
if (!list_empty(&dev->power.entry))
list_move_tail(&dev->power.entry, &list);
put_device(dev);
}
list_splice(&list, &dpm_list);
mutex_unlock(&dpm_list_mtx);
return error;
}
/**
* device_suspend - Save state and stop all devices in system.
* @state: PM transition of the system being carried out.
*
* Prepare and suspend all devices.
*/
int device_suspend(pm_message_t state)
{
int error;
might_sleep();
error = dpm_prepare(state);
if (!error)
error = dpm_suspend(state);
return error;
}
EXPORT_SYMBOL_GPL(device_suspend);
void __suspend_report_result(const char *function, void *fn, int ret)
{
if (ret)
printk(KERN_ERR "%s(): %pF returns %d\n", function, fn, ret);
}
EXPORT_SYMBOL_GPL(__suspend_report_result);